The marchers accuse officials of allowing themselves to be bribed in exchange for permits to put on shows in crowded and unsafe clubs.

Waving banners reading "Corruption Kills," the protesters demanded the resignations of Prime Minister Victor Ponta, deputy Gabriel Oprea, and the mayor of the Bucharest district, where the club was located.

Romanian prosecutors have ordered the three nightclub owners held for questioning.

Witnesses say indoor fireworks were set off inside the Colectiv nightclub, where the hard rock group Goodbye to Gravity was performing.

The foam-covered ceiling quickly burst into flames sending close to 400 people fleeing to the only exit.

Dozens of doctors are treating the injured, saying they are heartbroken to see so many young people whose lives have been changed forever.

While thousands marched in Bucharest Tuesday, the country honored two men that friends say were the heroes of Friday's tragedy.

President Klaus Iohannis posthumously decorated photographer Claudiu Petre and drummer Adrian Rugina. Both died while running into the burning nightclub to save others.

Iohannis said both will be remembered for "their courage and altruism and for saving lives at the cost of supreme sacrifice."